Multistage graphite precipitation through protracted fluid flow in sheared metagranitoid, Digana, Sri Lanka: evidence from stable isotopes

Binu-Lal, S.S.; Kehelpannala, K.V. Wilbert; Satish-Kumar, M.; Wada, Hideki

doi:10.1016/s0009-2541(02)00400-x

Cited by 35 publications

(29 citation statements)

References 46 publications

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“…A large number of papers have dealt with the isotopic characterization of graphite from vein deposits in Sri Lanka (e.g., Dobner et al 1978;Weis et al 1981;Binu-Lal et al 2003;Touzain et al 2010 Hoernes et al 1994).…”

Section: Mineralogy and Geochemistrymentioning

confidence: 99%

Vein graphite deposits: geological settings, origin, and economic significance

et al. 2013

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Graphite deposits result from the metamorphism of sedimentary rocks rich in carbonaceous matter or from precipitation from carbon-bearing fluids (or melts). The latter process forms vein deposits which are structurally controlled and usually occur in granulites or igneous rocks. The origin of carbon, the mechanisms of transport, and the factors control-ling graphite deposition are discussed in relation to their geological settings. Carbon in granulite-hosted graphite veins derives from sublithospheric sources or from decarbonation reactions of carbonate-bearing lithologies, and it is transported mainly in CO 2 -rich fluids from which it can precipitate. Graphite precipitation can occur by cooling, water removal by retrograde hydration reactions, or reduction when the CO 2 -rich fluid passes through relatively low-fO 2 rocks. In igneous settings, carbon is derived from assimilation of crustal mate-rials rich in organic matter, which causes immiscibility and the formation of carbon-rich fluids or melts. Carbon in these igneous-hosted deposits is transported as CO 2 and/or CH 4 and eventually precipitates as graphite by cooling and/or by hydration reactions affecting the host rock. Independently of the geological setting, vein graphite is characterized by its high purity and crystallinity, which are required for applica-tions in advanced technologies. In addition, recent discovery of highly crystalline graphite precipitation from carbon-bearing fluids at moderate temperatures in vein deposits might provide an alternative method for the manufacture of synthetic graphite suitable for these new applications.

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Section: Mineralogy and Geochemistrymentioning

confidence: 99%

Vein graphite deposits: geological settings, origin, and economic significance

et al. 2013

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“…According to Farquhar et al (1999) and Binu-Lal et al (2003), carbon isotope variations in graphite crystals precipitated from C-O-H fluids in both closed and open systems may result from (1) precipitation from a fluid with constant d 13 C but with changes in a fluid-graphite controlled by changes in temperature, (2) precipitation from a fluid with constant d 13 C but with changing composition (a fluid-graphite changes), (3) precipitation from a fluid with d 13 C varying according to graphite precipitation under Rayleigh conditions, and (4) precipitation from mixing of two isotopically different fluids (one CO 2 -rich and one CH 4 -rich). It must be pointed out that isotopic fractionations resulting from changes in carbon speciation in fluids or by mixing fluids (2 and 4) are large compared to those resulting from cooling of a fluid of fixed composition ).…”

Section: Fluid-graphite Carbon Fractionationmentioning

confidence: 99%

“…For instance, intracrystalline carbon isotope analyses in graphite from metagranitoid led Binu-Lal et al (2003) to infer that such a zonation pattern cannot be explained by a Rayleigh precipitation model. They suggest that it was caused by a drop in temperature during graphite deposition.…”

Section: C-o-h Fluids With a Single Carbon Speciesmentioning

confidence: 99%

“…In addition, heterogeneity of carbon isotope ratios within populations of graphite grains in a rock can be recognized in many fluid-deposited occurrences as well as carbon isotope zoning within single graphite crystals (e.g. Santosh and Wada, 1993a;Farquhar et al, 1999;Santosh et al, 2003;Binu-Lal et al, 2003;Satish-Kumar et al, 2011b). Considering the very sluggish kinetics of carbon diffusion in graphite (i.e., graphite can be considered isotopically inert to further alteration once crystallized; Wada, 1988), the isotopic composition of graphite grains is a very useful geochemical feature for detecting changing fluid regimes.…”

Section: Introductionmentioning

confidence: 99%

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Carbon isotopes of graphite: Implications on fluid history

Luque

Crespo-Feo

Barrenechea

et al. 2012

Geoscience Frontiers

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Stable carbon isotope geochemistry provides important information for the recognition of fundamental isotope exchange processes related to the movement of carbon in the lithosphere and permits the elaboration of models for the global carbon cycle. Carbon isotope ratios in fluid-deposited graphite are powerful tools for unravelling the ultimate origin of carbon (organic matter, mantle, or carbonates) and help to constrain the fluid history and the mechanisms involved in graphite deposition. Graphite precipitation in fluid-deposited occurrences results from CO 2 -and/or CH 4 -bearing aqueous fluids. Fluid flow can be considered as both a closed (without replenishment of the fluid) or an open system (with renewal of the fluid by successive fluid batches). In closed systems, carbon isotope systematics in graphite is mainly governed by Rayleigh precipitation and/or by changes in temperature affecting the fractionation factor between fluid and graphite. Such processes result in zoned graphite crystals or in successive graphite generations showing, in both cases, isotopic variation towards progressive 13 C or 12 C enrichment (depending upon the dominant carbon phase in the fluid, CO 2 or CH 4 , respectively). In open systems, in which carbon is episodically introduced along the fracture systems, the carbon systematics is more complex and individual graphite crystals may display oscillatory zoning because of Rayleigh precipitation or heterogeneous variations of d 13 C values when mixing of fluids or changes in the composition of the fluids are the mechanisms responsible for graphite precipitation. ª 2011, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.

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“…of various sources (e.g., mantle carbon, CO 2 from decarbonation reactions, CO 2 outgassed from melts etc. ; Weis et al, 1981;Mattey, 1987;Satish -Kumar et al, 2002;Binu -lal et al, 2003;Lamb and Valley, 1985;Pineau et al, 1987;Luque et al, 1992Luque et al, , 1998Luque et al, , 2009Farquhar et al, 1999). Stable isotopic composition of C is a powerful geochemical tool widely employed for interpretation of the origin/source of carbon, based on fractionation of carbon isotopes during various surface and subsurface processes.…”

Section: Introductionmentioning

confidence: 99%

Origin of graphite in glimmerite and spinellite in Achankovil Shear Zone, southern India

Rajesh

Arai

Satish-Kumar

2009

Journal of Mineralogical and Petrological Sciences

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We report occurrence and origin of graphite in glimmerite and spinellite from an unusual ultramafic complex in Achankovil Shear Zone (ACSZ) in southern India. Raman analyses of primary graphite flakes in close association with spinel and phlogopite confirm the highly crystalline nature. The carbon isotope composition ranges from -7‰ to -9.8‰ typical of mantle -derived graphite. A genetic model is proposed in which carbon was derived from a reduced juvenile mantle source linked to the genesis of volatile rich ultramafic rocks in ACSZ.

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Multistage graphite precipitation through protracted fluid flow in sheared metagranitoid, Digana, Sri Lanka: evidence from stable isotopes

Cited by 35 publications

References 46 publications

Vein graphite deposits: geological settings, origin, and economic significance

Vein graphite deposits: geological settings, origin, and economic significance

Carbon isotopes of graphite: Implications on fluid history

Origin of graphite in glimmerite and spinellite in Achankovil Shear Zone, southern India

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